In the installation and maintenance of transmission cable such as fiber optic cable, the removal of poly sheathing frequently presents difficulties in safeguarding the delicate transmission fibers contained within the sheath. The problem is especially precarious during optical fiber cable work when there is working service on the fiber cable. In such situations, the cable sheath frequently must be removed at a location distant from the ends of the cable (“mid-sheath”), making the task even more difficult. The industry standard approach to that problem is presently for the OSP technician to use hand-held cutting knives to remove the polyethylene and steel membranes from around the fiber cable. In performing that task, the OSP technician could slip and cut the cable, in which case service would be lost during the process. A tool is needed that would allow the polyethylene and steel sheaths to be removed without the danger of damaging the fiber cable.
Small hand tools further present danger to the OSP technician, who is exposed to the sharp blades of the hand knives as they are forced through the sheath and along the cable. A device is needed that would safely remove the poly sheath.
Several specialized tools have been proposed for removing cable sheathing. U.S. Pat. No. 5,533,264 to Wheary, issued Jul. 9, 1996 and incorporated herein by reference in its entirety, describes an apparatus for removing metallic or non-metallic cable sheathing using a single sharpened wheel cutting element attached to a chain that is rolled around the cable to make a circular cut. The apparatus may include a continuity measurement circuit for measuring continuity between the cutting element and a shield layer of the cable.
U.S. Pat. No. 6,581,291 to Tarpill et al., issued Jun. 24, 2003 and incorporated herein by reference in its entirety, describes a cable stripping tool that longitudinally slits the cable sheath using a blade that is adjustable using an adjustment screw. The sheath must be removed after slitting using conventional methods.
U.S. Pat. No. 6,044,744 to Eslambolchi et al., issued Apr. 4, 2000 and incorporated herein by reference in its entirety, describes a fiber optic cable sheath removal tool that uses an electrically driven cutting wheel to make circumferential and longitudinal cuts in the cable sheath. Depth of cut is adjusted using an adjusting mechanism that displaces cable guides toward or away from the cutting wheel. The tool is used to make cuts in both directions before the sheath is removed.
Each of the above-described tools cuts the cable sheath but does not remove the sheath during the cutting step. The sheath must be subsequently removed using an additional step with the tool or with hand tools.
There is therefore presently a need for a method and apparatus for removing a section of fiber optic cable sheath at a mid-sheath location on a cable in a quick and efficient manner, without damaging the fibers within the cable and without endangering the OSP technician. To the inventors' knowledge, there is currently no such apparatus or method employed to satisfactorily accomplish that task.